drm/radeon/kms: fix incorrect comparison in cayman setup code.

This was leading to a bogus value being programmed to the backend
routing register.

Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/ni.c

@@ -417,7 +417,7 @@ static u32 cayman_get_tile_pipe_to_backend_map(struct radeon_device *rdev,
 		num_shader_engines = 1;
 	if (num_shader_engines > rdev->config.cayman.max_shader_engines)
 		num_shader_engines = rdev->config.cayman.max_shader_engines;
-	if (num_backends_per_asic > num_shader_engines)
+	if (num_backends_per_asic < num_shader_engines)
 		num_backends_per_asic = num_shader_engines;
 	if (num_backends_per_asic > (rdev->config.cayman.max_backends_per_se * num_shader_engines))
 		num_backends_per_asic = rdev->config.cayman.max_backends_per_se * num_shader_engines;